Add Custom Field Type to Sugar Logic

I have a custom field type for an auto-increment field. Using this guide we have almost all the functionality we would like:

http://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_7.9/User_Interface/Fields/Creating_Custo… 

One exception is the field is not available to use in Sugar Logic. I have tracked down the function that populates this data to the cleanFields method in modules/ExpressionEngine/formulaHelper.php. Manually modifying this function adds the field to the select field list while building a Sugar Logic formula but I cannot figure out how to achieve this without modifying the core file.

Copying and extending to custom/modules/ExpressionEngine/formulaHelper.php didn't do the trick. I also copied and extended what I think is the view for this at custom/modules/ExpressionEngine/views/view.editformula.php but this didn't work either.

Any ideas on how to implement this for On-Demand environments?

Note that the class FormulaHelper at modules/ExpressionEngine/formulaHelper.php is auto-loaded in cache/class_map.php

Thank you